Transfer swi ch operating mechanism for effecting tap changes

ABSTRACT

A transfer switch including, in addition to main contacts, auxiliary contacts and current-carrying contacts, fixed terminals having current-carrying contact means. Special switching means allow selective interconnection of the fixed current-carrying contacts with current-carrying contact means of the fixed terminals. The movable main contacts, the movable auxiliary contacts, and the aforementioned special switching means are all operated by cam means, or a cam disc.

United States Patent Schaller [451 Apr. 23, 1974 TRANSFER SWICHOPERATING MECHANISM FOR EFFECTING TAP CHANGES Inventor: Johann Schaller,Regensburg,

Germany Machinenfabrik Reinhausen Gebruder Scheubeck K.G., Regensburg,Japan Filed: Mar. 14, 1973 Appl. No.: 341,310

Assignee:

US. Cl 200/18, 200/17 R, 200/11 TC, 200/153 R Int. Cl. H0lh 3/32 Fieldof Search 200/11 TC, l8, 17 R, 153 G, 200/153 H, 153 J, 153 P, 153 PA,153 R References Cited UNITED STATES PATENTS l/l972 Bleibtreu et al.n... ZOO/ll TC 3,360,618 12/1967 Schunda 200/11 Primary Examiner-JamesR. Scott Attorney, Agent, or Firm-Erwin Salzer [5 7] ABSTRACT A transferswitch including, in addition to main contacts, auxiliary contacts andcurrent-carrying contacts, fixed terminals having current-carryingcontact means. Special switching means allow selective interconnectionof the fixed current-carrying contacts with current-carrying contactmeans of the fixed terminals. The movable main contacts, the movableauxiliary contacts, and the aforementioned special switching means areall operated by cam means, or a cam disc.

4 Claims, 2 Drawing Figures PATEHTED APR 2 3 m4 SHLEI 2 OF 2 FIG. 2

TRANSFER SWICH OPERATING MECHANISM FOR EFFECTING TAP CHANGES BACKGROUNDOF THE INVENTION Tap-changing regulating transformers, and moreparticularly such transformers known as Jensen-type transformers,include three units, namely the transformer proper having a tappedwinding, selector switches for selecting desired taps of the winding,and transfer switches for transferring the load from one selected tap toanother.

The coaction of such units has been amply described in prior patents as,for instance, US. Pat. No. 3,176,089 to A. Bleibtreu et al., Mar. 30,1965 for LOAD TAP CHANGERS FOR TRANSFORMERS, U.S. Pat. No. 3,218,400 toA. Bleibtreu, Nov. 16, 1965 for TRANSFER SWITCHES FOR TAP CHANGINGREGULATING TRANSFORMERS HAVING SQUIR- REL-CAGE-SHAPED SUPPORT FOR THEFIXED CONTACTS THEREOF, and in U.S. Pat. No. 3,632,908 to A. Bleibtreuet al., Jan. 4, 1972 for REG- ULATING TRANSFORMER TAP CHANGER SWITCH.Reference may be had to the aforementioned patents in regard to generalinformation of the units of which a Jansen-type regulating transformeris made upfand the mode of operation thereof.

The movable contacts of transfer switches may be operated by variousmeans as, for instance, linkages, or cams. The present invention relatesto transfer switches whose movable contacts are operated by cams ratherthan by linkages or toggles.

Transfer switches include pairs of relatively movable main contacts. Inthis context the term main contacts is used in reference to contactswhich are intended to interconnect, and interconnect, a tap of a tappedtransformer winding directly with the terminal of an outgoing line, orload circuit. The term directly as used in this context means withoutinterposition of switching resistors, or switch-over resistors.

Transfer switches further'include pairs of relatively movable auxiliarycontacts. In this context the term auxiliary contact is used inreference to contacts which are intended to interconnect, andinterconnect, a tap of a tapped transformer winding with the terminal ofan outgoing line, or load circuit, by the intermediary of switchingresistors or switch-over resistors.

A third kind of contacts occurring in transfer switches as well as inmany other switches and circuit breakers are current-carrying contacts.Such contacts are designed to carry high load currents with very smalllosses, but are incapable of opening or closing live circuits.Current-carrying contacts of transfer switches interconnect directly,i.e. without interposition of a resistor, a tap of a tapped transformerwinding with the terminal of an outgoing line, or'load circuit.Currentcarrying contacts provide minimal resistance shunts across pairsof engaging main contacts.

Polyphase transfer switches for Jansen-type transformers including maincontacts, auxiliary contacts and current-carrying contacts operated bylinkages are shown in US. Pat. No. 3,671,687 to A. Bleibtreu, June 20,1972 for TRANSFER SWITCH FOR TAP- CHANGING REGULATING TRANSFORMERS IN-CLUDING LOST MOTION INTERCONNECTION DRIVING MECHANISM.

The present inventionrefers to transfer switches including auxiliarycontacts, main contacts and currentcarrying contacts, and moreparticularly transfer switches wherein these contacts are operated bycam means rather than'linkages, or toggles, and which are designed tocooperate with tapped polyphase or threephase transformers. In suchtransfer switches the fixed contacts are generally arranged at points ofa cylindrical surface, and this applies also to transfer switchesembodying the present invention.

The principal object of theinvention is to provide transfer switches ofthe above description whose bulk is minimized, i.e. which are extremelycompact.

A related object of this invention is to provide transfer switches ofthe above description allowing to greatly simplify the geometry of theirvarious current-paths.

Still another related object of this invention is to provide transferswitches of the above description whose current-carrying contacts maybe, or are, positioned immediately adjacent, or very close, to the maincontacts and to the auxiliary contacts.

Other objects of this invention will become apparent as thisspecification progresses.

SUMMARY OF THE INVENTION Tap changing transfer switches embodying thisinvention comprise the following elements:

a. A plurality of pairs of relatively movable auxiliary contactsincluding fixed auxiliary contacts arranged in a pattern that is asector of a circle.

b. Aplurality of pairs of relatively movable main contacts includingfixed main contacts arranged in said pattern of a sector of a circleperipherally outside the region of said sector occupied by said fixedauxiliary contacts.

c. Cam means driven by a shaft arranged in the center of said circle foroperating said relatively movable auxiliary contacts and said-relativelymovable main contacts.

d. Two pairs of fixed current-carrying contacts arranged on" anothercircle of relatively large diameter concentric to said circle, each pairof said two pairs of fixed current-carrying contacts being arrangedoutside the angular area defined by said center of a circle and saidfixed main contacts, and on opposite side of said area. 7

e. A pair of fixed substantially U-shaped terminals arranged on anothercircle of relatively small diameter concentric to said circle, each ofsaid pair of fixed terminals being arranged outside the angular areadefined by said center of a circle and said fixed main contacts and onopposite sides of said area, and each of said pair of fixedsubstantially U-shaped terminals supporting a pair of terminal contactson the flange portions thereof.

f. A pair of contact bridges for selectively connecting one fixedcurrent-carrying contact of said two pairs of fixed current-carryingcontacts and one terminal contact of said pair of terminal contacts ofsaid pair of terminals.

g. Operating means including cam means driven by said shaft foroperating said pair of contact bridges.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a sector of a three-phasetransfer switch embodying this invention which transfer switch includesthree sectors as shown in FIG. 1, FIG. 1 being in essence a top planview of the transfer switch, some of its parts having been removed tobetter expose other parts thereof; and

FIG. 2 is a vertical section of the structure shown in FIG. 1 takenalong II-II of FIG. 1 and being drawn on a smaller scale than FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, andmore particularly to FIG. 1 thereof, reference characters VS, US and WShave been applied to indicate the three sectors included in athree-phase transformer switch. Sectors VS and WS have been indicatedbut diagrammatically in FIG. 1, and sector US has been shown inconsiderable detail. Sectors VS and WS are constructed in the same wayas sector US.

The structure of FIG. 1 includes movable main contactsl, 4 and movableauxiliary contacts 2, 3. The aforementioned movable contacts 1, 2, 3, 4are operated by cam-controlled rods 9, i.e. these contacts are movedeither radially outwardly, or radially inwardly, by means ofcam-controlled rods 9. Reference characters 5 and 8 have been applied toindicate fixed main contacts cooperating with movable main contacts 1and 4, and reference characters 6 and 7 have been applied to indicatefixed auxiliary contacts cooperating with movable auxiliary contacts 2and 3. The ends of rods 9 remote from contacts 1, 2, 3, 4 are providedwith pins engaging slots 10 in cam disk 11. The latteris pivotable bymeans of shaft 12 arranged in the center thereof. Shaft 12 is adapted tobe pivoted by motor means (not shown) selectively either in clockwisedirection or in counterclockwise direction. Cam disk 11 pivots jointlywith shaft 12 and this causes rods 9 to move contacts 1, 2, 3, 4radially outwardly and radially inwardly in the required predeterminedsequence.

Reference characters D, and D, have been applied to generally designatecurrent-carrying contact means, i.e. contact means capable of carrying aload current continuously but not capable of performing any switchingoperations underv load. The current-carrying contact means D, includesthe fixed current-carrying contacts U, and W,, the fixedcurrent-carrying terminal 14 and the current-carrying bridge 13 whichconductively interconnectsparts U, and 14 in the position of the switchmechanism shown in FIG. 1. In that position movable main contact 1engages fixed main contact 5 and contacts 2, 3, 4 are out of engagementwith contacts 6, 7, 8. The fixed current-carrying contact W pertains interms of operation to sector WS rather than sector US. Thecurrent-carrying contact means D include the fixed current-carryingcontacts U V,, the fixed current-carrying terminal 15 and thecurrentcarrying bridge 16 which conductively interconnects parts V, and15 in the position of the switch mechanism shown in FIG. 1. The fixedcurrent-carrying contact V, pertains in terms of operation to the sectorVS rather than sector US of the polyphase switch mechanism. The fixedcurrent-carrying contacts U,, U V,, W, are arranged along a circle withdrive shaft 12 as its center and having a relatively large radius. Thechannel-.

shaped current-carrying terminals 14, 15 are arranged along anothercircle with drive shaft 12 as its center end having a relatively smallradius. The contact bridge 13 is adapted to conductively connectselectively either contact U, and contact 14 on a flange portion ofchannel-shaped current-carrying terminal 14, or contact W and contact142 on a flange portion of channel-shaped current-carrying terminal 14.In a like fashion contact bridge 16 is adapted to conductively connectselectively either contact V, and contact 151 on a flange ofchannel-shaped current-carrying terminal 15, or contact'U and contact152 on a flange of channelshaped current-carrying terminal contact 15.Currentcarrying contact bridge 13 is supported by a two armed lever 17pivotally supported at 19 by current-carrying terminal 14 and providedwith a roller 171 adapted to engage a cam-forming recess or cut-out 21in cam plate 1 1. In a like fashion current-carrying contact bridge 16is supported by a lever 18 having two arms pivotally supported at 20 bycurrent-carrying terminal 15 and provided with a roller 181 adapted toengage a camforming recess or cut-out 22 in cam plate 11. Referencenumerals 211 and 221 have been applied to indicate short cam sections oncam plate 11 immediately adjacent recesses 21 and 22, respectively. Camplate 11 may also be provided with cam means 213, 214 to both sides ofrecess 21 and cam means 223, 224 to both sides of recess 22. The objectof these various cam means will become more fully apparent from whatfollows below.

In FIG. 2 reference character 45 has been applied to indicate supportinginsulators which supports currentcarrying contacts V,, U

The supporting insulators 45 are on the other hand fixed on a contactsupporting segment 31 of insulating material together with terminals 15.

This contact supporting segment 31 supports also the fixed main contacts5, which are operating together with the movable main contact 1.

The movable main contact 1 is operated by rods 9 and connecting rods 42,said connection rods 42 are hinged together by a bridge 44 which isdriven by tension springs 43.

Consideringa tap-changing operation starting with the position of theconstituent elements of the structure from the positions thereof shownin FIG. 1. Such a tapchanging operation involves a counterclockwisepivotal motion of shaft 12 which is Y-shaped in cross-section andresults in a like pivotal motion of cam plate 11. As a result of such apivotal motion rollers 171, 181 which were heretofore resting againstcam surfaces 211, 221 of cam disc 11 are caused to engage recesses 21,22 of cam disc 11. This causes a pivotal motion of lever 17 about pivot19 in clockwise direction, and a pivotal motion of lever 18 about pivot20 in clockwise direction. As a result of that motion of lever 17contact bridge 13 moves out of engagement with contact surfaces U, and141 into a position intermediate fixed current-carrying contacts U, andW,. In like fashion the motion of lever 18 moves contact bridge 18 outof engagement with contact surfaces V, and 151 into a positionintermediate fixed current-carrying contacts V, and U In other words,the current-carrying paths between parts U, and 141 and parts V, and 151are eliminated. As the pivotal motion of parts 1 1 and 12 continues,movable auxiliary contact 2 engages fixed auxiliary contact 6 and themovable main contact parts from fixed main contact 5. Thereafter movablecontact 3 moves into engagement with fixed auxiliary contact 7, andshortly thereafter the movable auxiliary contact 2 parts from itscooperating fixed contact 6. As the tap-changing operation furtherprogresses movable main contact 4 engages fixed main contact 8 andmovable auxiliary contact 3 parts supporting lever 17 is pivotedresulting in engagement of current-carrying bridge 13 with contactsurfaces W and 142.

It will be understood that like contact motions as those described aboveoccur also in sectors VS and WS of the transfer switch, and that whenall parts of the switch mechanism are in their limit positions describedabove the direction of pivotal motion of shaft 12 and cam plate 11 maybe reversed, as a result of which all the parts of the switch mechanismare returned to their initial positions shown in FIG. 1.

The provision of cam surfaces 213, 214, 223, 224 is .desirable butoptional. The object of these cam surfaces is to initiate by positiveaction the pivotal motions of bridge-supporting levers l7 and 18. When atapchanging operation is initiated, i.e. when the pivotal action of camplate 11 just begins, cam surfaces 213, 214, 223, 224 engage instantlythe radially inner ends of levers 17, 18 and thus initiate the pivotalmotions thereof about pivots 19 and 20. l

It will be apparent from the above that fixed auxiliary contacts 6, 7cooperating with the movable auxiliary contacts 2, 3 are arranged in apattern-that is a sector of a circle, the center of which is the centerof shaft 12. The fixed main contacts 5, 8 cooperating with the movablemain contacts 1, 4 are likewise arranged in a pattern which is a sectorof a circle, the center of which is the center of'shaft 12. Fixed maincontacts 5, 8 are arranged peripherally outside the region of the sectorof a circle occupied by auxiliary fixed contacts 6, 7. Shaft 12 operatescam means 11, 10 for operating contacts 2, 3, 1, 4. Reference charactersU W have been applied to indicate a first pair of fixed currentcarrying'contacts arranged on another circle than contacts 5, 6, 7, 8. The circleon which contacts U W are arranged and the circle on which contacts 5,6, 7, 8 are arranged are concentric. Reference characters U V, have beenapplied to indicate a second pair of fixed current-carrying contactsarranged on the same circle as the aforementioned first pair of fixedcurrentcarrying contacts. Contacts U W and contacts U V are arrangedoutside of the angular area defined by the center of the circle on whichthey are arranged and by fixed main contacts 5, 8. Contacts U W andcontacts U V, are arranged on opposite sides of that area. The pair offixed terminals 1 4, is arranged on another circle concentric with theaforementioned circles, but having a relatively small diameter. Each ofterminals 14, 15 is'arranged outside the angular area defined by thecenter of shaft 12 and fixed main contacts 5, 8. Fixed terminals 14, 15are substantially U-shaped, and the flange portions thereof supportcurrent-carrying contacts 141, 142 and 151, 152, respectively. The pairof contact bridges 13, 16 are supported by two-armed levers 17, 18 whichare pivoted at 19 and 20, respectively. Each contact bridge 13, 16 isformed by a pair of contacts which are' biased in opposite directions byinterposed helical springs, but maintained in certain limit positions byabutments supported by, or forming part of, levers 17, 18. This has beenclearly shown in FIG. 1. Contact bridge 13 can selectively interconnectcontacts U and 141 (as shown in FIG. 1), or contacts W and 142. Contactbridge 16 can selectively interconnect contacts V, and 151 (as shown inFIG. 1), or contacts U and 152. This depends upon the position of shaft12 and cam disc 11. Cam disc 11 and the camforming slots 21, 22 thereinare the means for operating or actuating levers 17, 18 and contactbridges 13, 16.

I claim as my invention:

1. A tap-changing transfer switch for tapped regulating transformerscomprising a. a plurality of pairs of relatively movable auxiliarycontacts including fixed auxiliary contacts arranged in a pattern thatis a sector of a-circle;

b. a plurality of pairs of relatively movable main contacts includingfixed main contacts arranged in said pattern of a sector of a circleperipherally outside the region of said sector occupied by said fixedauxiliary contacts; 1

c. cam means driven by a pivotable shaft arranged in the center of saidcircle for operating said relatively movable auxiliary contacts and saidrelatively movable main contacts;

d. two pairs of fixed current-carrying contacts arranged on anothercircle of relatively large diameter concentric to said circle each pairof said two pairs of fixed current-carrying contacts being arrangedoutside the angular area defined by said center of a circle and saidfixed main contacts and on opposite sides of said area;

e. a pair of fixed substantially U-shaped terminals arranged on-anothercircle of relatively small diameter concentric to said circle, each ofsaid pair of fixed terminals being arranged outside the angular areadefined by said center of a circle and said fixed main contacts and onopposite sides of said area, and each of said pair of substantially U-shaped fixed terminals supporting a pair of terminal contacts on theflange portions thereof;

f. a pair of contact bridges for selectively connecting one fixedcurrent-carrying contact of said two pairs of fixed current-carryingcontacts and one terminal contact of said pair of terminal contacts ofsaid pair of terminals; and

g. operating means including cam means driven by said shaft foroperating said pair of contact bridges.

2. A switch as specified in claim 1 wherein a. said cam means foroperating said relatively movable auxiliary contacts and said relativelymovable main contacts are formed by a disc mounted on said shaft andhaving a plurality of contactoperating cam surfaces; and wherein b. saidoperating means for operating said pair of contact bridges include apair of two-armed levers pivotably supported between the ends thereof,supporting said contact bridges on one of the ends thereof and beingdriven at the other of the ends thereof by cam surfaces formed by saiddisc.

3. A switch as specified in claim 2 wherein the pivotal supports of saidtwo-armed levers are arranged between said flange portions of saidsubstantially U- shaped terminals.

4. A switch as specified in claim 2 wherein said disc is provided withabutment means for engaging said twoarmed levers in the limit positionsthereof and with slots for operating said two-armed levers incident topivotal motions of said disc.

5333 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 330 74 Dated A r. 23,. 1974 Inv n Johann Schaller It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

F a p p "1 Cover'pag'e, left column, line 8 Japan should read Germanyinsert after line l0 30] 7 Foreign Application Priority Data March 18,1972 Germany Signed and S sal-ed this twenty-fifth Day of November 1975ISEAL} AlteSl.

Rump. Mason 7 c. MARSHALL DANN A Q X Qfjuer (vmmixsiuncr ufPa-rents andTrademarks UNITED STATES PATENT OFFICE QE TIFICATE OF CORRECTIQN PatentNo. 3 0 74 Dated Apr. 23, 1974 Inventor(s) Johann Schaller It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below: Q 7

Cover page, left column, line 8 Japan should read Germany insert afterline 10 30] Foreign Q Application Priority Data March 18, 1972 GermanySigned and Sea-l ed this twenty-fifth Day Of November 1975 ISEAL}Arrest:

RU'PH C. MASON C. MARSHALL DANN ff (ummisxz'nncr uflarvnrs andTrademarks

1. A tap-changing transfer switch for tapped regulating transformerscomprising a. a plurality of pairs of relatively movable auxiliarycontacts including fixed auxiliary contacts arranged in a pattern thatis a sector of a circle; b. a plurality of pairs of relatively movablemain contacts including fixed main contacts arranged in said pattern ofa sector of a circle peripherally outside the region of said sectoroccupied by said fixed auxiliary contacts; c. cam means driven by apivotable shaft arranged in the center of said circle for operating saidrelatively movable auxiliary contacts and said relatively movable maincontacts; d. two pairs of fixed current-carrying contacts arranged onanother circle of relatively large diameter concentric to said circle,each pair of said two pairs of fixed current-carrying contacts beingarranged outside the angular area defined by said center of a circle andsaid fixed main contacts and on opposite sides of said area; e. a pairof fixed substantially U-shaped terminals arranged on another circle ofrelatively small diameter concentric to said circle, each of said pairof fixed terminals being arranged outside the angular area defined bysaid center of a circle and said fixed main contacts and on oppositesides of said area, and each of said Pair of substantially U-shapedfixed terminals supporting a pair of terminal contacts on the flangeportions thereof; f. a pair of contact bridges for selectivelyconnecting one fixed current-carrying contact of said two pairs of fixedcurrent-carrying contacts and one terminal contact of said pair ofterminal contacts of said pair of terminals; and g. operating meansincluding cam means driven by said shaft for operating said pair ofcontact bridges.
 2. A switch as specified in claim 1 wherein a. said cammeans for operating said relatively movable auxiliary contacts and saidrelatively movable main contacts are formed by a disc mounted on saidshaft and having a plurality of contact-operating cam surfaces; andwherein b. said operating means for operating said pair of contactbridges include a pair of two-armed levers pivotably supported betweenthe ends thereof, supporting said contact bridges on one of the endsthereof and being driven at the other of the ends thereof by camsurfaces formed by said disc.
 3. A switch as specified in claim 2wherein the pivotal supports of said two-armed levers are arrangedbetween said flange portions of said substantially U-shaped terminals.4. A switch as specified in claim 2 wherein said disc is provided withabutment means for engaging said two-armed levers in the limit positionsthereof and with slots for operating said two-armed levers incident topivotal motions of said disc.